U.S. patent application number 17/256050 was filed with the patent office on 2021-05-20 for fine bubble generation device and fine bubble generation method.
This patent application is currently assigned to NGK SPARK PLUG CO., LTD.. The applicant listed for this patent is NGK SPARK PLUG CO., LTD.. Invention is credited to Kazuteru HORIUCHI.
Application Number | 20210146318 17/256050 |
Document ID | / |
Family ID | 1000005403714 |
Filed Date | 2021-05-20 |
![](/patent/app/20210146318/US20210146318A1-20210520-D00000.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00001.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00002.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00003.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00004.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00005.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00006.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00007.png)
![](/patent/app/20210146318/US20210146318A1-20210520-D00008.png)
![](/patent/app/20210146318/US20210146318A1-20210520-P00899.png)
United States Patent
Application |
20210146318 |
Kind Code |
A1 |
HORIUCHI; Kazuteru |
May 20, 2021 |
FINE BUBBLE GENERATION DEVICE AND FINE BUBBLE GENERATION METHOD
Abstract
A fine bubble generation device in one aspect of the present
disclosure is a device that generates fine bubbles in a liquid by
causing the liquid to pass through a porous element having many
pores. In the fine bubble generation device, a differential
pressure is applied between first and second sides of the element,
and, by the applied differential pressure, the liquid disposed on
the first side of the element is passed through the element and is
jetted toward the second side to thereby generate fine bubbles. In
this fine bubble generation device, the flow speed of the liquid
during passage through the element is 0.009769 [m/s] or higher. The
fine bubbles can thereby be generated efficiently.
Inventors: |
HORIUCHI; Kazuteru;
(Nagoya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NGK SPARK PLUG CO., LTD. |
Nagoya-shi |
|
JP |
|
|
Assignee: |
NGK SPARK PLUG CO., LTD.
Nagoya-shi
JP
|
Family ID: |
1000005403714 |
Appl. No.: |
17/256050 |
Filed: |
June 28, 2019 |
PCT Filed: |
June 28, 2019 |
PCT NO: |
PCT/JP2019/025955 |
371 Date: |
December 24, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01F 2215/0431 20130101;
B01F 2215/045 20130101; B01F 5/0287 20130101; B01F 5/0692 20130101;
B01F 2215/0422 20130101; B01F 3/04751 20130101; B01F 3/04758
20130101 |
International
Class: |
B01F 3/04 20060101
B01F003/04; B01F 5/06 20060101 B01F005/06; B01F 5/02 20060101
B01F005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 28, 2018 |
JP |
2018-123241 |
Claims
1. A fine bubble generation device that generates fine bubbles in a
liquid by causing the liquid to pass through a porous element
having many pores, the fine bubble generation device comprising: a
differential pressure applying section that applies a differential
pressure between first and second sides of the element; and a
bubble generating section configured such that, by the differential
pressure applied by the differential pressure applying section, the
liquid disposed on the first side of the element is passed through
the element and is jetted toward the second side to thereby
generate fine bubbles, wherein the flow speed of the liquid during
passage through the element is 0.009769 [m/s] or higher.
2. The fine bubble generation device according to claim 1, wherein
the element has an average pore diameter of 1.5 .mu.m to 500
.mu.m.
3. The fine bubble generation device according to claim 1, wherein
the element has a surface porosity of 24% to 47.7%.
4. The fine bubble generation device according to claim 1, wherein
the contact angle of the liquid on a surface of the element is
38.8.degree. to 151.32.degree..
5. The fine bubble generation device according to claim 1, wherein
the element is formed of a ceramic.
6. The fine bubble generation device according to claim 1, further
comprising: a first tank formed integrally with the element; and a
second tank that receives the liquid jetted from the element.
7. The fine bubble generation device according to claim 6, wherein
the first tank has a gas supply section serving as the differential
pressure applying section so as to supply a gas to the first tank,
the gas applying the differential pressure, and a liquid supply
section for supplying the liquid to the first tank.
8. The fine bubble generation device according to claim 6, wherein
the second tank has a liquid withdrawing section for withdrawing
the jetted liquid to the outside.
9. A fine bubble generation method for generating fine bubbles in a
liquid by causing the liquid to pass through a porous element
having many pores, the method comprising the step of generating the
fine bubbles by applying a differential pressure between first and
second sides of the element to thereby cause the liquid disposed on
the first side of the element to pass through the element and be
jetted toward the second side, wherein the flow speed of the liquid
during passage through the element is set to 0.009769 [m/s] or
higher.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National Phase Application under
35 U.S.C. .sctn. 371 of international patent application
PCT/JP2019/025955 filed on Jun. 28, 2019 and claims the benefit of
priority to Japanese Patent Application No. 2018-filed with the
Japanese Patent Office on Jun. 28, 2018, all of which are
incorporated by reference in their entirety. The International
Application was published in Japanese on Jan. 2, 2020 as
International Publication No. WO/2020/004653 under PCT Article
21(2).
FIELD OF THE INVENTION
[0002] The present disclosure relates to a fine bubble generation
device and a fine bubble generation method for generating fine
bubbles in a liquid.
BACKGROUND OF THE INVENTION
[0003] The usefulness of a liquid containing very small bubbles
called fine bubbles has recently been receiving attention.
Specifically, attention has been given to a technique for a liquid
(e.g., water) containing fine bubbles of various gases (i.e., a
fine bubble liquid).
[0004] It has been contemplated to utilize the technique using such
fine-bubble-containing liquid, for example, for washing of
components etc., disinfection and deodorization of water,
sterilization with ozone gas, health and medical fields,
purification of water in lakes, ponds, and farms, treatment of
wastewater from plants, stock farms, etc., growth promotion in
agriculture and fishery, production of functional water such as
hydrogen water, etc.
[0005] Known examples of the device that generates fine bubbles
include devices of various types such as a pressurized dissolution
type, a fine pore type, a static mixer type, and a spiral liquid
flow type. In particular, devices of the fine pore type in which
fine bubbles are generated using a porous material have recently
been proposed (see Japanese Patent Application Laid-Open (kokai)
No. 2017-170278 and Japanese Patent Application Laid-Open (kokai)
No. 2017-47374) because of their advantages such as a simple
structure.
[0006] For example, Japanese Patent Application Laid-Open (kokai)
No. 2017-170278 discloses a technique in which a liquid is caused
to flow inside a porous pipe (i.e., through through-holes) and a
high-pressure gas is supplied to the outer side of the porous pipe
to generate fine bubbles in the liquid in the porous pipe.
[0007] Japanese Patent Application Laid-Open (kokai) No. 2017-47374
discloses a technique in which a porous pipe is submerged in a
liquid and a high-pressure gas is supplied to the porous pipe to
generate fine bubbles in the liquid on the outer side of the porous
pipe.
[0008] Various techniques regarding fine bubble other than the
above techniques have been proposed (see Japanese Patent
Application Laid-Open (kokai) No. 2002-301345 and Japanese Patent
Application Laid-Open (kokai) No. 2017-217585). For example,
Japanese Patent Application Laid-Open (kokai) No. 2002-301345 and
Japanese Patent Application Laid-Open (kokai) No. 2017-217585
disclose a technique in which a porous member formed of a resin or
a metal is used to reduce the size of bubbles contained in water in
a pre-stage tank. In this technique, large air bubbles contained in
the water in the pre-stage tank are sheared (i.e., the air bubbles
are cut finely into bubbles having smaller diameters), to thereby
produce fine bubbles.
PRIOR ART DOCUMENTS
Patent Documents
[0009] Japanese Patent Application Laid-Open (kokai) No.
2017-170278 Japanese Patent Application Laid-Open (kokai) No.
2017-47374 Japanese Patent Application Laid-Open (kokai) No.
2002-301345 Japanese Patent Application Laid-Open (kokai) No.
2017-217585
Problems to be Solved by the Invention
[0010] In the techniques described in Japanese Patent Application
Laid-Open (kokai) No. 2017-170278 and Japanese Patent Application
Laid-Open (kokai) No. 2017-47374, fine bubbles are generated in a
liquid in the following manner. The liquid is placed inside a
porous pipe, and a high-pressure gas is supplied from the outer
side of the porous pipe. Alternatively, the liquid is placed on the
outer side of a porous pipe, and a high-pressure gas is supplied
from the inner side of the porous pipe. However, a problem with
these techniques is that fine bubbles cannot be generated
efficiently.
[0011] For example, one problem with the conventional techniques is
that the amount of generatable fine bubbles is small as compared
with the amount of the high-pressure gas (gas amount) mixed into
the liquid to generate the fine bubbles.
[0012] In the techniques described in Japanese Patent Application
Laid-Open (kokai) No. 2002-301345 and Japanese Patent Application
Laid-Open (kokai) No. 2017-217585, it is necessary to shear bubbles
in the pre-stage tank. This is not preferable because the device
structure and the operating process are complicated.
[0013] In one aspect of the present disclosure, it is preferable to
provide a fine bubble generation device and a fine bubble
generation method that can generate fine bubbles in a liquid
efficiently.
SUMMARY OF THE INVENTION
Means for Solving the Problems
[0014] (1) A fine bubble generation device in one aspect of the
present disclosure relates to a fine bubble generation device that
generates fine bubbles in a liquid by causing the liquid to pass
through a porous element having many pores. The fine bubble
generation device includes a differential pressure applying section
and a bubble generating section.
[0015] In this fine bubble generation device, the differential
pressure applying section applies a differential pressure between
first and second sides of the element. The bubble generating
section is configured such that, by the differential pressure
applied by the differential pressure applying section, the liquid
disposed on the first side of the element is passed through the
element and is jetted toward the second side to thereby generate
fine bubbles. When the fine bubbles are generated, the flow speed
of the liquid during passage through the element is 0.009769 [m/s]
or higher.
[0016] The upper limit of the flow speed may be 1500 [m/s].
[0017] First, the reason why the flow speed in the fine bubble
generation device is specified to be 0.009769 [m/s] or higher will
be described.
[0018] In recent years, there is a movement of standardization of
fine bubble water. Specifically, "fine bubble water is defined as
water prepared by subjecting pure water (blank water) to fine
bubble generation treatment to increase the concentration of
bubbles by at least one order of magnitude" (the standardization is
discussed in FBIA (Fine Bubble Industries Association)).
[0019] As for the bubble concentration of pure water (blank water)
used for experiments described later (i.e., the bubble
concentration of the pure water before the generation of fine
bubbles), Max (the maximum value) is 2.98 E+06 [bubbles/mL], and
Ave (the average value) is 1.22 E+06 [bubbles/mL], as can be seen
from Table 8 described later. Notably, for example, E+06 means
10.sup.6 and, as is well known, is exponent notation representing
the exponent of 10.
[0020] Therefore, in this fine bubble generation device, 6.82 E+07
[bubbles/mL] is determined as a reference value for increasing the
bubble concentration by at least one order of magnitude, and a flow
speed necessary to obtain a bubble concentration higher than the
reference value is specified. The specified flow speed enables
efficient generation of fine bubbles.
[0021] As described above, in the first aspect, since the liquid
passes through the porous element at a flow speed of 0.009769 [m/s]
or higher due to the differential pressure applied by, for example,
a gas, fine bubbles can be generated efficiently as described later
in Experimental Examples.
[0022] Namely, a liquid with a high bubble concentration (i.e., a
fine bubble liquid) can be easily produced without mixing a gas
into the liquid under high pressure as in the conventional
techniques. Even in the case of, for example, pure water, the
bubble concentration can be easily increased.
[0023] In this fine bubble generation device, fine bubbles can be
generated efficiently, by causing the liquid disposed on the first
side of the element to pass through the element and be jetted
toward the second side; i.e., by passing the liquid through the
element at least one time.
[0024] As described above, in this fine bubble generation device,
the flow speed of the liquid during passage through the fine pores
in the porous element is equal to or higher than the prescribed
value. This enables efficient generation of fine bubbles.
Therefore, fine bubbles can be easily generated using a small
device without using a conventional facility provided with a large
pump, etc. For example, when the differential pressure is generated
using a gas supplied from a gas cylinder, a pump, a power supply,
etc. can be omitted.
[0025] The following reason is presumed as the reason why fine
bubbles can be generated efficiently by specifying the flow speed
in the manner described above.
[0026] Presumably, when a liquid passes though pores (i.e., very
small regions) in the porous element at a high flow speed,
cavitation occurs locally in the pores. The cavitation causes rapid
energy changes such as changes in pressure and changes in amount of
heat. As a result, many bubble nuclei (i.e., seeds of fine bubbles)
are generated, and many fine bubbles are generated from the bubble
nuclei.
[0027] (2) In the above-described fine bubble generation device,
the element may have an average pore diameter of 1.5 .mu.m to 500
.mu.m.
[0028] By using the element having the above average pore diameter,
fine bubbles can be generated efficiently, as will be clear from
the Experimental Examples described later. Moreover, a high bubble
concentration can be achieved.
[0029] (3) In the above-described fine bubble generation device,
the element may have a surface porosity of 24% to 47.7%.
[0030] By using the element having the above surface porosity, fine
bubbles can be generated efficiently, as will be clear from the
Experimental Examples described later. Moreover, a high bubble
concentration can be achieved.
[0031] (4) In the above-described fine bubble generation device,
the contact angle of the liquid on a surface of the element may be
38.8.degree. to 151.32.degree..
[0032] By using the element having the above liquid contact angle,
fine bubbles can be generated efficiently, as will be clear from
the Experimental Examples described later. Moreover, a high bubble
concentration can be achieved.
[0033] (5) In the above-described fine bubble generation device,
the element may be formed of a ceramic.
[0034] The element formed of a ceramic as described above is
preferable because the amount of impurities (i.e., contamination)
contained in the liquid in which the fine bubbles are generated is
small. When the fine bubble generation device is used in, for
example, the medical field, the food field, etc., it is preferable
that the amount of impurities is small. Therefore, it is preferable
to use the ceramic-made element in these fields.
[0035] Another advantage of the ceramic-made element is that
deterioration due to erosion is small.
[0036] (6) The above-described fine bubble generation device may
further comprise a first tank formed integrally with the element,
and a second tank that receives the liquid jetted from the
element.
[0037] By using the device described above, the liquid containing
fine bubbles can be easily produced. In this device, the liquid is
placed in the first tank and supplied from the first tank to the
first side of the element. The liquid is jetted toward the second
side to thereby generate fine bubbles, and the liquid containing
the fine bubbles can be received by the second tank.
[0038] (7) In the above-described fine bubble generation device,
the first tank may have a gas supply section serving as the
differential pressure applying section so as to supply a gas to the
first tank, the gas applying the differential pressure, and a
liquid supply section for supplying the liquid to the first tank.
Notably, the gas supply section is an example of the differential
pressure applying section.
[0039] In this fine bubble generation device, the gas that applies
the differential pressure can be supplied to the first tank using
the gas supply section of the first tank, and the liquid can be
supplied to the first tank using the liquid supply section of the
first tank.
[0040] (8) In the above-described fine bubble generation device,
the second tank may have a liquid withdrawing section for
withdrawing the jetted liquid to the outside.
[0041] In this fine bubble generation device, the jetted liquid can
be withdrawn to the outside using the liquid withdrawing section of
the second tank.
[0042] (9) A fine bubble generation method in another aspect of the
present disclosure relates to a fine bubble generation method for
generating fine bubbles in a liquid by causing the liquid to pass
through a porous element having many pores.
[0043] In this fine bubble generation method, by applying the
differential pressure between the first and second sides of the
element, the liquid disposed on the first side of the element is
passed through the element and is jetted toward the second side to
thereby generate fine bubbles. For generation of the fine bubbles,
the flow speed of the liquid during passage through the element is
set to 0.009769 [m/s] or higher.
[0044] The fine bubble generation method has the same effects as
those of the above fine bubble generation device.
<The Structure of the Present Disclosure Will Next be
Described>
[0045] The porous element is a porous member having many pores
formed therein (i.e., communicating holes through which the liquid
can pass). Examples of this element include a tubular member
through which the liquid can pass from the inner side to the outer
side or from the outer side to the inner side, a tubular member
having a closed forward end, and a tubular member having opposite
open ends. Other examples include a film-shaped (e.g.,
plate-shaped) member through which the liquid can pass from one
side to the other side. [0046] Examples of the material of the
element include materials formed of a ceramic (for example, at
least one of alumina, mullite, zirconia, titania, silica, magnesia,
and calcia), various resins (such as polyethylene, polypropylene,
polyethylene terephthalate, and polytetrafluoroethylene), and
metals (such as aluminum, titanium, iron, gold, silver, copper,
stainless steel). For example, a sintered product containing 97% by
weight of alumina may be used for the element. In particular, the
material of the element is preferably a material formed of any of
the above ceramics. [0047] The liquid used may be water (such as
pure water, tap water, or deionized water), alcohol, seawater, an
aqueous solution, a cleaning fluid, an organic solvent, etc.
Generally, a small amount of various gasses such as an ambient gas
are dissolved in the liquid. [0048] The fine bubbles are bubbles
having a diameter of 100 .mu.m (10.sup.-4 m) or less as defined by
the International Organization for Standardization (ISO) and
include micro-bubbles having a diameter of 1 .mu.m or more and less
than 100 .mu.m and ultra-fine bubbles having a diameter of less
than 1 .mu.m. Examples of the gas contained in the fine bubbles
include various gases such as hydrogen, oxygen, carbon dioxide, and
air. [0049] Examples of the method for setting the flow speed to
the above range include a method in which the differential pressure
applied to the liquid in which fine bubbles are to be generated is
adjusted. For example, the flow speed can be increased by
increasing the differential pressure by increasing the pressure
applied to the liquid before it passes through the element.
[0050] Examples of the method for applying the differential
pressure include a method in which the pressure applied to the
first side (liquid side) of the element is increased by, for
example, supplying a high-pressure gas (i.e., a method in which the
atmospheric pressure is increased). For example, the differential
pressure can be applied using a gas supplied from a gas cylinder.
Another example of the method for applying the differential
pressure is reducing by, for example, evacuation, the pressure
(e.g., atmospheric pressure) applied to the second side of the
element (the side on which fine bubbles are generated). [0051] The
flow speed [m/s] can be determined, for example, by computing Q/S
using the flow rate (Q [m.sup.3/s]) of the liquid flowing from the
first side (liquid side) of the element to the second side (the
side on which fine bubbles are generated) and the total area (S
[m.sup.2]) of opening portions (i.e., pore portions) of the surface
on the second side of the element. The maximum value of the flow
speed is 1500 m/s, which is the maximum transmission speed of
ultrasonic waves generated in water. [0052] The surface porosity of
the element is the ratio of the total area of the opening portions
(pore portions) of the surface of the element on the second side
(the side on which fine bubbles are generated) to the total surface
area of the element on the second side.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 is an illustration showing a fine bubble generation
device of a first embodiment.
[0054] FIG. 2 is a graph showing the relation between gas
consumption and bubble concentration in the fine bubble generation
device of the first embodiment and in a conventional fine pore-type
device.
[0055] FIG. 3 is an illustration showing a fine bubble generation
device of a second embodiment.
[0056] FIG. 4 is an illustration showing a fine bubble generation
device of a third embodiment.
[0057] FIG. 5 is an illustration showing a fine bubble generation
device of a fourth embodiment.
[0058] FIG. 6 is an illustration showing an element used in
Experimental Example 1 and names of dimensions of the element.
[0059] FIG. 7A is a graph showing the characteristics of liquids of
samples in Experimental Example 4, specifically, their pH values;
FIG. 7B is a graph showing the characteristics of the liquids of
the samples in Experimental Example 4, specifically, their electric
conductivities; and FIG. 7C is a graph showing the characteristics
of the liquids of the samples in Experimental Example 4,
specifically, their ATP values.
[0060] FIG. 8A is a graph showing the characteristics of the
liquids of the samples in Experimental Example 4, specifically,
their TOC values, and FIG. 8B is a graph showing the
characteristics of the liquids of the samples in Experimental
Example 4, specifically, their ICP-MS values.
[0061] FIG. 9A is a graph showing the characteristics of liquids of
samples in Experimental Example 5, specifically, their particle
concentrations before and after freezing, and FIG. 9B is a graph
showing the characteristics of the liquids of the samples in
Experimental Example 5, specifically, their particle concentrations
with the concentrations before defoaming set to 100.
DESCRIPTION OF REFERENCE NUMERALS
[0062] 1, 71, 91, 101 fine bubble generation device [0063] 3, 103
first tank [0064] 5, 105 second tank [0065] 9 gas supply section
[0066] 10 differential pressure applying section [0067] 11 liquid
supply section [0068] 13 liquid withdrawing section [0069] 31
bubble generating section [0070] 33, 75, 97, 107 element
DETAILED DESCRIPTION OF THE INVENTION
[0071] Embodiments of a fine bubble generation device and a fine
bubble generation method to which the present disclosure is applied
will be described with reference to the drawings.
1. FIRST EMBODIMENT
1-1. Overall Structure
[0072] The structure of a fine bubble generation device of a first
embodiment will be described.
[0073] As shown in FIG. 1, the fine bubble generation device 1 of
the first embodiment is a device that generates fine bubbles in a
liquid (water such as pure water) and includes a box-shaped device
body 7 including a first tank 3 and a second tank 5; a gas supply
section 9 that supplies a gas (e.g., nitrogen gas) to the first
tank 3; a liquid supply section 11 that supplies the liquid to the
first tank 3; and a liquid withdrawing section 13 that withdraws
the liquid (i.e., the liquid containing fine bubbles generated
therein: fine bubble liquid) from the second tank. The details will
be described below.
<First Tank>
[0074] The first tank 3 is a container that can store the liquid
and is configured such that its interior can be pressurized.
Specifically, the first tank 3 has an airtight structure for
preventing the liquid and the gas from flowing out, except portions
through which the liquid is supplied and flows out and a portion
through which the gas flows into the first tank 3.
[0075] A gas introduction port 17 for introducing the gas supplied
from the gas supply section 9 into the first tank 3 is provided in
a side wall 15 thereof, and a liquid introduction port 21 for
introducing a liquid supplied from the liquid supply section 11 is
provided in an upper portion 19 of the first tank 3. Notably, the
gas introduction port 17 is disposed at a position that is above
the level of the liquid placed in the first tank 3.
[0076] A liquid supply port 25 for supplying the liquid to the
second tank 5 side is provided at a bottom 23 of the first tank 3,
and a stainless steel-made cylindrical communication pipe 27
extending vertically downward is attached to the liquid supply port
25 such that a space on the first tank 3 side and a space on the
second tank 5 side are in communication with each other. The liquid
in the first tank 3 is supplied to the second tank 5 side through
the communication pipe 27.
[0077] Moreover, a first pressure sensor 29 for detecting the
pressure (air pressure) inside the first tank 3 is disposed in the
first tank 3.
[0078] The first tank 3 having the airtight structure and the gas
supply section 9 form a structure for applying a differential
pressure (i.e., a differential pressure applying section 10).
<Second Tank>
[0079] The second tank 5 is a container capable of containing a
liquid (i.e., the fine bubble liquid) and includes a bubble
generating section 31 disposed therein and configured to generate
fine bubbles.
[0080] The bubble generating section 31 includes the communication
pipe 27 and a porous element 33 connected to the lower end of the
communication pipe 27. Therefore, the element 33 is integrated with
the first tank 3 through the communication pipe 27.
[0081] The element 33 is a pipe-shaped (specifically, a circular
cylindrical) member having a closed lower end (i.e., a forward
end), and the upper end of the element 33 is fitted onto the
communication pipe 27, joined to the communication pipe 27 using an
adhesive and a metal joint (not shown), and is in contact with the
communication pipe 27 with no gap therebetween. The lower end of
the element 33 is closed by a bottom 35 that is part of the element
33.
[0082] The element 33 is a porous sintered body containing, for
example, alumina (Al.sub.2O.sub.3), which is a ceramic, as a main
component (e.g., 97% by weight of alumina) and 3% by weight of a
ceramic such as silica (SiO.sub.2), calcia (CaO), or magnesia (MgO)
as the remainder. Many pores (i.e., communication pores through
which the liquid can pass) are formed over the entire sintered
body. Namely, the element 33 is a ceramic porous sintered body. The
sintered body has a single layer structure (i.e., a symmetric
structure) in which many pores are present in the same state (e.g.,
having the same average pore diameter).
[0083] Specifically, the average pore diameter of the element 33 is
within the range of 1.5 .mu.m to 500 .mu.m, and the surface
porosity of the element 33 is within the range of 24% to 47.7%. The
contact angle of the liquid (e.g., water) on the surface of the
element 33 is within the range of 38.8.degree. to
151.32.degree..
[0084] A liquid withdrawing port 39 for withdrawing the liquid from
the second tank 5 to the outside is disposed in a lower portion of
a side wall 37 of the second tank 5, and the liquid withdrawing
section 13 is connected to the liquid withdrawing port 39.
[0085] Further, a second pressure sensor 41 for detecting the
pressure (air pressure) inside the second tank 5 is disposed in the
second tank 5.
<Peripheral Structure>
[0086] The gas supply section 9 includes a gas cylinder 43 filled
with a gas, a first pipe 45 connecting the gas cylinder 43 to the
gas introduction port 17, a first on-off valve 47 for opening and
closing the flow channel of the first pipe 45, and a third pressure
sensor 49 for detecting the pressure inside the gas cylinder
43.
[0087] The liquid supply section 11 includes a second pipe 51
connected to the liquid introduction port 21 to supply the liquid
to the first tank 3 and a second on-off valve 53 for opening and
closing the flow channel of the second pipe 51. Although not
illustrated, a tank or the like for storing the liquid is disposed
on the upstream side of the second pipe 51.
[0088] The liquid withdrawing section 13 includes a third pipe 55
connected to the liquid withdrawing port 39 to withdraw the liquid
to the outside and a third on-off valve 57 for opening and closing
the flow channel of the third pipe 55.
1-2. Operation of Fine Bubble Generation Device
[0089] Next, the operation of the fine bubble generation device 1
will be described.
[0090] First, with the first on-off valve 47 and the third on-off
valve 57 closed, the second on-off valve 53 is opened to supply a
prescribed amount (e.g., VO [mL]) of the liquid from the second
pipe 51 to the first tank 3. Then, the second on-off valve 53 is
closed. In this case, the liquid in the first tank 3 flows through
the communication pipe 27 into the element 33 (i.e., flows into an
inner space 59).
[0091] Next, the first on-off valve 47 is opened to supply a
high-pressure gas from the gas cylinder 43 into the first tank 3.
As a result, the pressure inside the first tank 3 becomes higher
than, for example, the atmospheric pressure (e.g., 0.4 MPa).
[0092] When the pressure inside the first tank 3 increases as
described above, the liquid in the first tank 3 is pressurized, and
the liquid in the element 33 is also pressurized.
[0093] When the liquid inside the element 33 is pressurized, the
liquid inside the element 33 passes through the pores on a wall
surface 61 of the element 33 and is jetted at high speed to the
outside of the element 33 (i.e., an outer space 63 in the second
tank).
[0094] In this case, the flow speed of the liquid during passage
through the element 33 is 0.009769 m/s or higher. When the liquid
passes through the element 33 at such a high speed, many fine
bubbles are generated. Specifically, a fine bubble liquid
containing the fine bubbles is obtained.
1-3. Method for Producing Element
[0095] A method for producing the element 33 will be described.
Since the element 33 can be produced by a routine method, the
method will be described briefly.
[0096] For example, 97% by weight of alumina powder having an
average particle size of 5 .mu.m and 3% by weight of sintering aid
powder such as SiO.sub.2 or MgO powder were prepared as solid
materials for the element 33.
[0097] Then, methyl cellulose, water, and a release agent were
added to these solid powders to produce kneaded clay, and a
closed-end cylindrical compact was formed using the kneaded
clay.
[0098] Then the compact was dried and fired at 1500.degree. C. in
an air atmosphere for 3 hours to thereby obtain the element 33
having the above-described structure.
[0099] As is well known, the average pore diameter can be adjusted
by controlling the particle diameters of the raw material powders.
As is well known, the surface porosity can be adjusted by
controlling the amount of the solid powders, the amount of the
organic material, and the amount of water.
1-4. Effects
[0100] (1) In the first embodiment, since the differential pressure
applied by the gas causes the liquid to pass through the porous
element 33 at a flow speed of 0.009769 [m/s] or higher, fine
bubbles can be efficiently generated.
[0101] For example, as shown in FIG. 2, in a conventional fine
pore-type device (a device available from company C described
later), the bubble concentration increases as the gas consumption
increases. In the fine bubble generation device 1 of the first
embodiment (i.e., the present type), a high bubble concentration
can be obtained with less gas consumption than that of the fine
pore-type device. The gas consumption in the present type in FIG. 2
is the consumption of the gas used for pressurization.
[0102] Specifically, a liquid having a high bubble concentration
(i.e., a fine bubble liquid) can be easily produced without mixing
a gas into a liquid under high pressure as in the conventional
device. For example, even in the case of pure water, the bubble
concentration can be easily increased.
[0103] (2) In the first embodiment, fine bubbles can be generated
efficiently by causing the liquid disposed on the first side of the
element 33 to pass through the element 33 and be jetted toward the
second side; i.e., by passing the liquid through the element 33 at
least one time (hereinafter referred to as "one pass").
[0104] (3) As descried above, in the first embodiment, fine bubbles
are generated efficiently by setting the flow speed of the liquid
during passage through the pores of the porous element 33 to a
prescribed value or greater. Therefore, fine bubbles can be easily
generated without using a conventional facility provided with a
large pump etc., i.e., by using a small device. Specifically, by
generating a differential pressure using the gas supplied from the
gas cylinder 43, the pump, a power supply, etc., can be
omitted.
[0105] (4) In the first embodiment, the average pore diameter of
the element 33 is within the range of 1.5 .mu.m to 500 .mu.m.
Therefore, fine bubbles can be generated efficiently. Moreover, a
high bubble concentration can be achieved.
[0106] (5) In the first embodiment, the surface porosity of the
element is within the range of 24% to 47.7%. Therefore, fine
bubbles can be generated efficiently. Moreover, a high bubble
concentration can be achieved.
[0107] (6) In the first embodiment, the contact angle of the liquid
on the surface of the element 33 is within the range of
38.8.degree. to 151.32.degree.. Therefore, fine bubbles can be
generated efficiently. Moreover, a high bubble concentration can be
achieved.
[0108] (7) In the first embodiment, the element 33 is formed of a
material containing a ceramic as a main component. Therefore, the
amount of impurities (i.e., contamination) contained in the liquid
in which the fine bubbles are generated is small, so that the
element 33 is suitable for a field that prefers less impurities
such as the medical field.
[0109] When the element 33 contains a ceramic as a main component,
there is also an advantage in that deterioration due to erosion is
small.
1-5. Correspondence Between Terms
[0110] The fine bubble generation device 1, the first tank 3, the
second tank 5, the gas supply section 9, the differential pressure
applying section 10, the liquid supply section 11, the liquid
withdrawing section 13, the bubble generating section 31, the
element 33 in the first embodiment correspond to examples of the
fine bubble generation device, the first tank, the second tank, the
gas supply section, the differential pressure applying section, the
liquid supply section, the liquid withdrawing section, the bubble
generating section, the element, respectively, in the present
disclosure.
2. SECOND EMBODIMENT
[0111] Next, a second embodiment will be described, but description
of the same details as those in the first embodiment will be
omitted or simplified.
[0112] As shown in FIG. 3, in a fine bubble generation device 71 of
the second embodiment, an element 75 similar to that in the first
embodiment is disposed in a single tank 73, and a communication
pipe 77 is connected to the upper end of the element 75.
[0113] The communication pipe 77 extends to the outside of the tank
73, and an on-off valve 79 is disposed in the communication pipe 77
on the outer side of the tank 73.
[0114] In the second embodiment, by opening the on-off valve 79, a
liquid (e.g., water) to which a prescribed pressure is applied is
supplied from the communication pipe 77 to the interior of the
element 75 (i.e., an inner space 81). Thus, fine bubbles can be
generated in the liquid, as in the first embodiment. Notably, the
fine bubble liquid can be supplied to an outer space 83 around the
element 75.
[0115] The structure for withdrawing the fine bubble liquid from
the tank 73 is the same as that in the first embodiment.
[0116] The effects of the second embodiment are the same as those
of the first embodiment. An advantage of the second embodiment is
that the structure can be simpler than that in the first
embodiment.
3. THIRD EMBODIMENT
[0117] Next, a third embodiment will be described, but description
of the same details as those in the first embodiment will be
omitted or simplified.
[0118] The third embodiment is the same as the first embodiment
except for the structure of the bubble generating section, and
therefore the bubble generating section will be described.
[0119] As shown in FIG. 4, the bubble generating section 93 of a
fine bubble generation device 91 of the third embodiment is formed
by connecting a cylindrical tubular element 97 to the lower end of
a communication pipe 95.
[0120] The element 97 is open at opposite ends in its axial
direction (in the vertical direction in FIG. 4). The upper end is
connected to the communication pipe 95, and the lower end is closed
with a cap 99. The cap 99 has a circular columnar shape and is a
dense sintered body formed of, for example, alumina.
[0121] The third embodiment has the same effects as those of the
first embodiment.
4. FOURTH EMBODIMENT
[0122] Next, a fourth embodiment will be described, but description
of the same details as those in the first embodiment will be
omitted or simplified.
[0123] In the fourth embodiment, the element used is a plate-shaped
member.
[0124] As shown in FIG. 5, a fine bubble generation device 101 of
the fourth embodiment has a structure in which a second tank 105 is
disposed below a first tank 103, as in the first embodiment.
[0125] A flat plate-shaped element 107 is disposed horizontally
between the first tank 103 and the second tank 105 so as to
separate the first tank 103 and the second tank 105 from each
other. The element 107 is positioned and fixed by a support member
111 disposed on a side wall 109.
[0126] In FIG. 5, other structures (e.g., structures for supplying
gas and liquid to the first tank 103) are omitted.
[0127] In the fourth embodiment also, by supplying liquid to the
first tank 103 and supplying gas to pressurize the liquid, the
liquid is caused to pass through the element 107, and fine bubbles
can thereby be generated in the liquid. Namely, a fine bubble
liquid can be supplied to the second tank 105 below the element
107.
[0128] The structure for withdrawing the fine bubble liquid from
the second tank 105 is the same as that in the first
embodiment.
[0129] The fourth embodiment has the same effects as those in the
first embodiment.
5. EXPERIMENTAL EXAMPLES
[0130] Experimental Examples conducted to examine the effects of
the present disclosure will be described. The liquid used was pure
water.
5-1. Experimental Example 1
<Details of Experiment>
[0131] In Experimental Example 1, as a device for generating fine
bubbles, there was used a fine bubble generation device having the
same structure as that in the first embodiment in which elements
similar to that in the third embodiment were used.
[0132] Sixty one samples (samples Nos. 1 to 59) shown in Tables 1
to 6 were produced as elements used for the experiment. In Tables 1
to 6, samples of Examples (Examples 1 to 32) are within the scope
of the present disclosure, and samples of Comparative Examples
(Comparative Examples 1 to 27) are outside the scope of the present
disclosure.
[0133] In Tables 1 and 2, the Examples and the Comparative Examples
are shown in ascending order of sample number. In Tables 3 and 4,
only the Examples are shown. In Tables 5 and 6, only the
Comparative Examples are shown.
[0134] In Experimental Example 1, fine bubbles were generated under
the conditions shown in Tables 1 to 6 below, and the flow speed of
liquid during passage through each element, etc. were determined as
shown in Tables 2, 4, and 6 below.
[0135] Table 7 shows a plurality of Comparative Examples and a
plurality of Examples selected as examples from the samples
described in Tables 1 to 6. In Table 7, each preferable sample
realizing a bubble concentration of 6.82 E+0.7 or more is
determined to be "acceptable," and each of the remaining
unpreferable samples is determined to be "unacceptable."
[0136] The experimental conditions and the experimental results
shown in Tables 1 to 7 will be described.
TABLE-US-00001 TABLE 1 Element data Bubble point Effective Element
Contact pressure area of Surface Pore outer Element Film Element
Element angle (pure water) element porosity diameter diameter
length thickness No. structure material [.degree.] [MPaG]
[mm.sup.2] [%] [nm] [mm] [mm] [mm] Ex. 1 1 Symmetric Alumina 43.55
0.1406 3240 31 1500 12 270 1.5 Ex. 2 2 Symmetric Alumina 43.55
0.1406 3240 31 1500 12 270 1.5 Ex. 3 3 Symmetric Alumina 43.55
0.1406 3240 31 1500 12 270 1.5 Comp. Ex. 1 4 Asymmetric Alumina
31.4 3.1048 3240 42 80 12 270 1.5 Comp. Ex. 2 5 Asymmetric Alumina
31.4 3.1048 3240 42 80 12 270 1.5 Ex. 4 6 Symmetric Alumina 43.81
0.0210 3240 24 10000 20 300 4 Ex. 5 7 Symmetric Alumina 43.81
0.0210 6000 24 10000 20 300 4 Ex. 6 8 Symmetric Alumina 43.81
0.0210 6000 24 10000 20 300 4 Ex. 7 9 Symmetric Alumina 49.23
0.0127 6000 24 15000 20 300 4 Ex. 8 10 Symmetric Alumina 49.23
0.0127 6000 24 15000 20 300 4 Ex. 9 11 Symmetric Alumina 49.23
0.0127 6000 24 15000 20 300 4 Comp. Ex. 3 12 Asymmetric Alumina
109.08 -1.1891 3240 42 80 12 270 1.5 Comp. Ex. 4 13 Asymmetric
Alumina 109.08 -1.1891 3240 42 80 12 270 1.5 Comp. Ex. 5 14
Asymmetric Alumina 109.08 -1.1891 3240 42 80 12 270 1.5 Comp. Ex. 6
15 Asymmetric Alumina 123.6 -2.0130 3240 42 80 12 270 1.5 Comp. Ex.
7 16 Asymmetric Alumina 123.6 -2.0130 3240 42 80 12 270 1.5 Comp.
Ex. 8 17 Asymmetric Alumina 123.6 -2.0130 3240 42 80 12 270 1.5
Comp. Ex. 9 18 Asymmetric Alumina 37.05 1.1613 3240 55 200 12 270
1.5 Comp. Ex. 10 19 Asymmetric Alumina 37.05 1.1613 3240 55 200 12
270 1.5 Comp. Ex. 11 20 Asymmetric Alumina 37.05 1.1613 3240 55 200
12 270 1.5 Comp. Ex. 12 21 Asymmetric Alumina 40.15 0.5561 3240 55
400 12 270 1.5 Comp. Ex. 13 22 Asymmetric Alumina 40.15 0.5561 3240
55 400 12 270 1.5 Comp. Ex. 14 23 Asymmetric Alumina 40.15 0.5561
3240 55 400 12 270 1.5 Comp. Ex. 15 24 Symmetric Alumina 87.53
0.0084 3240 31 1500 12 270 1.5 Ex. 10 25 Symmetric Alumina 87.53
0.0084 3240 31 1500 12 270 1.5 Ex. 11 26 Symmetric Alumina 87.53
0.0084 3240 31 1500 12 270 1.5 Comp. Ex. 16 27 Symmetric Alumina 1
1.32 -0.1702 3240 31 1500 12 270 1.5 Comp. Ex. 17 28 Symmetric
Alumina 151.32 -0.1702 3240 31 1500 12 270 1.5 Ex. 12 29 Symmetric
Alumina 151.32 -0.1702 3240 31 1500 12 270 1.5 Ex. 13 30 Symmetric
Alumina 38.8 0.0756 3240 38 3000 12 270 1.5 Ex. 14 31 Symmetric
Alumina 38.8 0.0756 3240 38 3000 12 270 1.5 Ex. 15 32 Symmetric
Alumina 38.8 0.0756 3240 38 000 12 270 1.5 Comp. Ex. 18 33
Asymmetric Aluminosilicate 60.41 261.2599 1440 55 0.55 16 90 2
Comp. Ex. 19 34 Asymmetric Aluminosilicate 60.41 261.2599 1440 55
0.55 16 90 2 Comp. Ex. 20 35 Asymmetric Aluminosilicate 60.41
261.2599 1440 55 0.55 16 90 2 Ex. 16 36 Symmetric Alumina 43.28
0.0042 15000 30 50000 50 300 12.5 Ex. 17 37 Symmetric Alumina 43.28
0.0042 15000 30 50000 50 300 12.5 Ex. 18 38 Symmetric Alumina 43.28
0.0042 15000 30 50000 50 300 12.5 Ex. 19 39 Symmetric Alumina 42.85
0.0021 15000 30 100000 50 300 12.5 Ex. 20 40 Symmetric Alumina
42.85 0.0021 15000 30 100000 50 300 12.5 Ex. 21 41 Symmetric
Alumina 42.85 0.0021 15000 30 100000 50 300 12.5 Comp. Ex. 21 42
Symmetric Alumina 50.01 0.3117 180 30 600 6 30 1 Comp. Ex. 22 43
Symmetric Alumina 50.01 0.3117 180 30 600 6 30 1 Comp. Ex. 23 44
Symmetric Alumina 50.01 0.3117 180 30 600 6 30 1 Ex. 22 45
Symmetric Alumina 38.8 0.0756 360 38 3000 12 30 1.5 Ex. 23 46
Symmetric Alumina 38.8 0.0756 360 38 3000 12 30 1.5 Ex. 24 47
Symmetric Alumina 38.8 0.0756 360 38 3000 12 30 1.5 Comp. Ex. 24 48
Symmetric Alumina 50.01 0.3117 1380 30 800 6 230 1 Comp. Ex. 25 49
Symmetric Alumina 50.01 0.3117 1380 30 800 6 230 1 Ex. 25 50
Symmetric Alumina 43.94 0.0004 15000 40 500000 50 300 12.5 Ex. 26
51 Symmetric Alumina 43.94 0.0004 15000 40 500000 50 300 12.5 Ex.
27 52 Symmetric Alumina 43.94 0.0004 15000 40 500000 50 300 12.5
Comp. Ex. 26 53 Symmetric Metal 64 0.0003 1385.4423 47.7 500000 42
Flat plate 1.3 Ex. 28 54 Symmetric Metal 64 0.0003 1385.4423 47.7
500000 42 Flat plate 1.3 Ex. 29 55 Symmetric Metal 64 0.0003
1385.4423 47.7 500000 42 Flat plate 1.3 Comp. Ex. 27 56 Symmetric
Resin 72 0.0225 900 40 4000 15 60 3 Ex. 30 57 Symmetric Resin 72
0.0225 900 40 4000 15 60 3 Ex. 31 58 Symmetric Resin 72 0.0225 900
40 4000 15 60 3 Ex. 32 59 Symmetric Resin 72 0.0225 900 40 4000 15
60 3 indicates data missing or illegible when filed
TABLE-US-00002 TABLE 2 Flow speed test data Time until Solvent
Applied entire solvent Results Solvent amount pressure passes
through Flow rate Q Pore area A Flow speed V Nanosight (NS-300)
Condition No. type [mL] [MPaG] [sec.] [m.sup.2/s] [m.sup.2] [m/s]
A.sup.Note B.sup.Note C.sup.Note Ex. 1 1 Pure water 200 0.1 14.37
0.00001392 1.00440E-03 0.013857 98.5 1.46E+08 7.3 Ex. 2 2 Pure
water 200 0.5 4.94 0.00004049 1.00440E-03 0.040308 91.2 2.33E+08
11.6 Ex. 3 3 Pure water 200 0.9 3.01 0.00006 45 1.00440E-03
0.066154 10 . 3.71E+08 18.5 Comp. Ex. 1 4 Pure water 200 0.1 393.09
0.00000051 1.3 080E-03 0.000374 111.7 1.56E+07 0.8 Comp. Ex. 2 5
Pure water 200 0.5 148.98 0.00000135 1.3 080E-03 0.000988 90.0
2.26E+07 1.1 Ex. 4 6 Pure water 200 0.1 4.9 0.00004016 1.44000E-03
0.027889 107.7 1.99E+08 10.0 Ex. 5 7 Pure water 200 0.5 3. 8
0.00005025 1.44000E-03 0.034897 91.8 3.03E+08 15.2 Ex. 6 8 Pure
water 200 0.9 2.501 0.00007 7 1.44000E-03 0.055533 122.4 2.88E+08
14.4 Ex. 7 9 Pure water 200 0.1 3.66 0.00005464 1.44000E-03
0.037948 99. 2.78E+08 13.9 Ex. 8 10 Pure water 200 0.5 2.549
0.00007846 1.44000E-03 0.064488 106.0 3.96E+08 19.8 Ex. 9 11 Pure
water 200 0.9 2.321 0.00006617 1.44000E-03 0.069840 94. 4.12E+08
20.6 Comp. Ex. 3 12 Pure water 200 0.1 700 0.00000029 1.3 080E-03
0.000210 100.3 1.08E+07 0.5 Comp. Ex. 4 13 Pure water 200 0.5 300
0.00000067 1.3 080E-03 0.000490 99.6 2.58E+07 1.3 Comp. Ex. 5 14
Pure water 200 0.9 120 0.000001 7 1.3 080E-03 0.001225 107.
4.80E+07 2.4 Comp. Ex. 6 15 Pure water 200 0.1 254 0.00000003 1.3
080E-03 0.000024 102.3 3.98E+06 0.2 Comp. Ex. 7 16 Pure water 200
0.5 1754 0.00000011 1.3 080E-03 0.000084 98.8 8.78E+06 0.4 Comp.
Ex. 8 17 Pure water 200 0.9 803.54 0.0000002 1.3 080E-03 0.000183
99. 9.98E+06 0.5 Comp. Ex. 9 18 Pure water 200 0.1 3 9 0.00000054
1.78200E-03 0.000304 82.4 2.42E+07 1.5 Comp. Ex. 10 19 Pure water
200 0.5 126.8 0.00000158 1.78200E-03 0.000885 108.0 4.60E+07 2.3
Comp. Ex. 11 20 Pure water 200 0.9 28.87 0.0000 3 1.78200E-03
0.003888 9 .1 6.30E+07 3.2 Comp. Ex. 12 21 Pure water 200 0.1 219.5
0.00000091 1.78200E-03 0.000511 102.6 3.88E+07 1.9 Comp. Ex. 13 22
Pure water 200 0.5 38.91 0.00000514 1.78200E-03 0.002884 7 .1
4.88E+07 2.4 Comp. Ex. 14 23 Pure water 200 0.9 13.34 0.00001499
1.78200E-03 0.008413 79.8 6.76E+07 2.9 Comp. Ex. 15 24 Pure water
200 0.1 112.7 9 0.00000177 1.00440E-03 0.0017 127.7 6.48E+07 2.7
Ex. 10 25 Pure water 200 0.5 14.747 0.00001358 1.00440E-03 0.013503
95.3 8.18E+07 4.1 Ex. 11 26 Pure water 200 0.9 10.057 0.00001989
1.00440E-03 0.019800 109.0 1.34E+08 6.7 Comp. Ex. 16 27 Pure water
200 0.1 621.9 0.00000032 1.00440E-03 0.000320 91.5 4.28E+07 2.1
Comp. Ex. 17 28 Pure water 200 0.5 40.19 0.00000498 1.00440E-03
0.004 55 121.7 5.68E+07 2. Ex. 12 29 Pure water 200 0.9 17.81
0.00001123 1.00440E-03 0.011180 121.2 6.82E+07 3.4 Ex. 13 30 Pure
water 200 0.1 10.182 0.00001984 1.23120E-03 0.015 54 96.8 6.98E+07
3.5 Ex. 14 31 Pure water 200 0.5 3.7 0.00005333 1.23120E-03
0.043318 95.0 2.03E+08 10.2 Ex. 15 32 Pure water 200 0.9 2.77
0.00007220 1.23120E-03 0.068644 88.8 3.45E+08 17.2 Comp. Ex. 18 33
Pure water 200 0.1 29285 0.00000001 7.92000E-04 0.000009 89.6
2.38E+0 0.1 Comp. Ex. 19 34 Pure water 200 0.5 110 1 0.00000002
7.92000E-04 0.000023 98. 6.18E+0 0.3 Comp. Ex. 20 35 Pure water 200
0.9 5845 0.00000003 7.92000E-04 0.000043 102.3 8.58E+0 0.4 Ex. 16
36 Pure water 200 0.1 2.39 0.00008368 4.50000E-03 0.018596 102.2
2.4 E+08 12.3 Ex. 17 37 Pure water 200 0.5 1.88 0.00010638
4.50000E-03 0.023 41 100.6 2.87E+08 14.3 Ex. 18 38 Pure water 200
0.9 1.51 0.00013245 4.50000E-03 0.02 433 90. 3.10E+08 15.5 Ex. 19
39 Pure water 200 0.1 2.25 0.00008889 4.50000E-03 0.01 753 96.5
2.58E+08 12.9 Ex. 20 40 Pure water 200 0.5 1.95 0.00010256
4.50000E-03 0.022792 9 .0 2.68E+08 13.3 Ex. 21 41 Pure water 200
0.9 1.25 0.0001 000 4.50000E-03 0.035556 94.5 2.86E+08 14.3 Comp.
Ex. 21 42 Pure water 200 0.1 2001.36 0.00000010 5.40000E-05
0.001851 102.6 2.38E+07 1.2 Comp. Ex. 22 43 Pure water 200 0.5 995.
5 0.00000020 5.40000E-05 0.003720 104.4 5.82E+07 2.9 Comp. Ex. 23
44 Pure water 200 0.9 780.41 0.0000002 5.40000E-05 0.00474 101.4
5.10E+07 2.6 Ex. 22 45 Pure water 200 0.1 82.47 0.00000243 1.3
800E-04 0.017728 119.8 1.53E+08 7. Ex. 23 46 Pure water 200 0.5
16.03 0.000001248 1.3 800E-04 0.0 1203 108.9 5.32E+08 26.6 Ex. 24
47 Pure water 200 0.9 11.99 0.000001668 1.3 800E-04 0.121 34 7.0
6.24E+08 31.2 Comp. Ex. 24 48 Pure water 200 0.1 78 0.000000025
4.14400E-04 0.000613 .7 4. 6E+07 2.5 Comp. Ex. 25 49 Pure water 200
0.5 301.47 0.0000000 4.14400E-04 0.001 02 149.2 4.76E+07 2.4 Ex. 25
50 Pure water 200 0.1 1.8 0.000105 2 6.00000E-03 0.017 37 102.4 2.7
E+08 13.8 Ex. 26 51 Pure water 200 0.5 1.11 0.00018018 6.00000E-03
0.0 0030 101.5 3.12E+08 15.6 Ex. 27 52 Pure water 200 0.9 0.99
0.00020202 6.00000E-03 0.033 70 98.5 3.42E+08 17.1 Comp. Ex. 26 53
Pure water 200 0.1 2 0.00000385 6.60440E-04 0.00 824 112.7 3.72E+07
1.9 Ex. 28 54 Pure water 200 0.5 31 0.00000 45 6.60440E-04 0.00 7 9
102.5 7.30E+07 3.7 Ex. 29 55 Pure water 200 0.9 22 0.00000909
6.60440E-04 0.0137 5 80.2 1. 2E+08 8.1 Comp. Ex. 27 56 Pure water
200 0.005 644 0.00000031 3. 0000E-04 0.000863 99.9 2.20E+07 1.1 Ex.
30 57 Pure water 200 0.1 14.87 0.0000134 3. 0000E-04 0.037361 102.2
5.50E+07 2.8 Ex. 31 58 Pure water 200 0.5 5.89 0.00003515 3.
0000E-04 0.097637 112.5 1.78E+08 8. Ex. 32 59 Pure water 200 0.9
3.88 0.00006155 3. 0000E-04 0.143184 9 .4 2.70E+08 13.5 .sup.Note
A: Bubble diameter [nm] B: Bubble concentration [bubbles/mL] C:
Bubble concentration [particles/frame] indicates data missing or
illegible when filed
TABLE-US-00003 TABLE 3 Element data Bubble point Effective Element
Contact pressure area of Surface Pore outer Element Film Element
Element angle (pure water) element porosity diameter diameter
length thickness No. structure material [.degree.] [MPaG]
[mm.sup.2] [%] [nm] [mm] [mm] [mm] Ex. 1 1 Symmetric Alumina 43.55
0.1406 3240 31 1500 12 270 1.5 Ex. 2 2 Symmetric Alumina 43.55
0.1406 3240 31 1500 12 270 1.5 Ex. 3 3 Symmetric Alumina 43.55
0.1406 3240 31 1500 12 270 1.5 Ex. 4 6 Symmetric Alumina 43.81
0.0210 6000 24 10000 20 300 4 Ex. 5 7 Symmetric Alumina 43.81
0.0210 6000 24 10000 20 300 4 Ex. 6 8 Symmetric Alumina 43.81
0.0210 6000 24 10000 20 300 4 Ex. 7 9 Symmetric Alumina 49.23
0.0127 6000 24 15000 20 300 4 Ex. 8 10 Symmetric Alumina 49.23
0.0127 6000 24 15000 20 300 4 Ex. 9 11 Symmetric Alumina 49.23
0.0127 6000 24 15000 20 300 4 Ex. 10 25 Symmetric Alumina 87.53
0.0084 3240 31 1500 12 270 1.5 Ex. 11 28 Symmetric Alumina 87.53
0.0084 3240 31 1500 12 270 1.5 Ex. 12 29 Symmetric Alumina 151.32
-0.1702 3240 31 1500 12 270 1.5 Ex. 13 30 Symmetric Alumina 38.8
0.075 3240 38 3000 12 270 1.5 Ex. 14 31 Symmetric Alumina 38.8
0.075 3240 38 3000 12 270 1.5 Ex. 15 32 Symmetric Alumina 38.8
0.075 3240 38 3000 12 270 1.5 Ex. 16 36 Symmetric Alumina 43.28
0.0042 15000 30 50000 50 300 12.5 Ex. 17 37 Symmetric Alumina 43.28
0.0042 15000 30 50000 50 300 12.5 Ex. 18 38 Symmetric Alumina 43.28
0.0042 15000 30 50000 50 300 12.5 Ex. 19 39 Symmetric Alumina 42.85
0.0021 15000 30 100000 50 300 12.5 Ex. 20 40 Symmetric Alumina
42.85 0.0021 15000 30 100000 50 300 12.5 Ex. 21 41 Symmetric
Alumina 42.85 0.0021 15000 30 100000 50 300 12.5 Ex. 22 45
Symmetric Alumina 38.8 0.0758 360 38 3000 12 30 1.5 Ex. 23 46
Symmetric Alumina 38.8 0.0758 360 38 3000 12 30 1.5 Ex. 24 47
Symmetric Alumina 38.8 0.0758 360 38 3000 12 30 1.5 Ex. 25 50
Symmetric Alumina 43.94 0.0004 1 000 40 500000 50 300 12.5 Ex. 26
51 Symmetric Alumina 43.94 0.0004 1 000 40 500000 50 300 12.5 Ex.
27 52 Symmetric Alumina 43.94 0.0004 1 000 40 500000 50 300 12.5
Ex. 28 54 Symmetric Metal 64 0.0003 1385.44236 47.7 500000 42 Flat
plate 1.3 Ex. 29 55 Symmetric Metal 64 0.0003 1385.44236 47.7
500000 42 Flat plate 1.3 Ex. 30 57 Symmetric Resin 72 0.0225 900 40
4000 15 60 3 Ex. 31 58 Symmetric Resin 72 0.0225 900 40 4000 15 60
3 Ex. 32 5 Symmetric Resin 72 0.0025 900 40 4000 15 60 3 indicates
data missing or illegible when filed
TABLE-US-00004 TABLE 4 Flow speed test data Time until Solvent
Applied entire solvent Results Solvent amount pressure passes
through Flow rate Q Pore Area A Flow speed V Nanosight (NS-300)
Condition No. type [mL] [MPaG] [sec.] [m.sup.2/s] [m.sup.2] [m/s]
A.sup.Note B.sup.Note C.sup.Note Ex. 1 1 Pure water 200 0.1 14.37
0.00001392 1.00440E-03 0.013857 98.5 1.46E+08 7.3 Ex. 2 2 Pure
water 200 0.5 4.94 0.00004049 1.00440E-03 0.040308 91.2 2.33E+08
11.3 Ex. 3 3 Pure water 200 0.9 3.01 0.0000 45 1.00440E-03 0.066154
10 .0 3.71E+08 18.5 Ex. 4 6 Pure water 200 0.1 4.98 0.00004016
1.44000E-03 0.027889 107.7 1.99E+08 10.0 Ex. 5 7 Pure water 200 0.5
3.98 0.00005025 1.44000E-03 0.034897 91.8 3.03E+08 15.2 Ex. 6 8
Pure water 200 0.9 2.501 0.00007997 1.44000E-03 0.056633 122.4
2.88E+08 14.4 Ex. 7 9 Pure water 200 0.1 3. 0.00005464 1.44000E-03
0.037948 99.5 2.78E+08 13.9 Ex. 8 10 Pure water 200 0.5 2.54
0.0000784 1.44000E-03 0.054488 10 .0 3.98E+08 19.8 Ex. 9 11 Pure
water 200 0.9 2.321 0.00008617 1.44000E-03 0.059840 94. 4.12E+08
20. Ex. 10 25 Pure water 200 0.5 14.747 0.00001356 1.00440E-03
0.013503 9 .3 8.18E+07 4.1 Ex. 11 26 Pure water 200 0.9 10.067
0.00001989 1.00440E-03 0.019800 109.0 1.34E+08 6.7 Ex. 12 29 Pure
water 200 0.9 17.81 0.00001123 1.00440E-03 0.011180 121.2 . 2E+07
3.4 Ex. 13 30 Pure water 200 0.1 10.182 0.00001954 1.23120E-03
0.015 54 96.8 5.98E+07 3.5 Ex. 14 31 Pure water 200 0.5 3.7
0.00005333 1.23120E-03 0.043318 95.0 2.03E+08 10.2 Ex. 15 32 Pure
water 200 0.9 2.77 0.00007220 1.23120E-03 0.058644 88.8 3.45E+08
17.2 Ex. 16 36 Pure water 200 0.1 2.39 0.000083 8 4.50000E-03 0.018
102.2 2.4 E+08 12.3 Ex. 17 37 Pure water 200 0.5 1.88 0.00010 3
4.50000E-03 0.023 41 100.6 2.87E+08 14.3 Ex. 18 38 Pure water 200
0.9 1. 1 0.0001324 4.50000E-03 0.02 433 90.0 3.10E+08 15.5 Ex. 19
39 Pure water 200 0.1 2.2 0.00008889 4.50000E-03 0.019753 9 .5 2.6
E+08 12.9 Ex. 20 40 Pure water 200 0.5 1.95 0.0001025 4.50000E-03
0.022792 98.0 2.8 E+08 13.3 Ex. 21 41 Pure water 200 0.9 1.2
0.00016000 4.50000E-03 0.03555 94.5 2.8 E+08 14.3 Ex. 22 45 Pure
water 200 0.1 2.47 0.00000243 1.36800E-04 0.017728 119.8 1. 3E+08
7. Ex. 23 46 Pure water 200 0.5 1 .03 0.0000124 1.36800E-04
0.091203 10 .9 5.32E+08 26. Ex. 24 47 Pure water 200 0.9 11.99
0.000016 8 1.36800E-04 0.121934 97.0 5.24E+08 31.2 Ex. 25 50 Pure
water 200 0.1 1.89 0.00010 82 6.00000E-03 0.017 37 102.4 2.76E+08
13.8 Ex. 26 51 Pure water 200 0.5 1.11 0.00018018 6.00000E-03
0.030030 101.5 3.12E+08 15. Ex. 27 52 Pure water 200 0.9 0.99
0.00020202 6.00000E-03 0.033 70 9 .5 3.42E+08 17.1 Ex. 28 54 Pure
water 200 0.5 31 0.00000645 6.60440E-04 0.0097 102.5 7. 0E+07 3.7
Ex. 29 55 Pure water 200 0.9 22 0.0000090 6.60440E-04 0.013765 80.2
1. 2E+08 8.1 Ex. 30 57 Pure water 200 0.1 14.87 0.00001345
3.60000E-04 0.037381 102.2 . 0E+07 2.8 Ex. 31 58 Pure water 200 0.5
5. 9 0.00003516 3.60000E-04 0.097637 112. 1.78E+08 8.9 Ex. 32 59
Pure water 200 0.9 3.88 0.00005155 3.60000E-04 0.143184 98.4
2.70E+08 1 .5 Ave. -- 100.80 -- .sup.Note A: Bubble diameter [nm]
B: Bubble concentration [bubbles/mL] C: Bubble concentration
[particles/frame] indicates data missing or illegible when
filed
TABLE-US-00005 TABLE 5 Element data Bubble point Effective Element
Contact pressure area of Surface Pore outer Element Film Element
Element angle (pure water) element porosity diameter diameter
length thickness No. structure material [.degree.] [MPaG]
[mm.sup.2] [%] [nm] [mm] [mm] [mm] Comp. Ex. 1 4 Asymmetric Alumina
31.4 3.1048 3240 42 80 12 270 1.5 Comp. Ex. 2 5 Asymmetric Alumina
31.4 3.1048 3240 42 80 12 270 1.5 Comp. Ex. 3 12 Asymmetric Alumina
109.08 -1.1891 3240 42 80 12 270 1.5 Comp. Ex. 4 13 Asymmetric
Alumina 109.08 -1.1891 3240 42 80 12 270 1.5 Comp. Ex. 5 14
Asymmetric Alumina 123.6 -1.1891 3240 42 80 12 270 1.5 Comp. Ex. 6
15 Asymmetric Alumina 123.6 -2.0130 3240 42 80 12 270 1.5 Comp. Ex.
7 16 Asymmetric Alumina 123.6 -2.0130 3240 42 80 12 270 1.5 Comp.
Ex. 8 17 Asymmetric Alumina 123.6 -2.0130 3240 42 80 12 270 1.5
Comp. Ex. 9 18 Asymmetric Alumina 37.05 1.1613 3240 42 200 12 270
1.5 Comp. Ex. 10 19 Asymmetric Alumina 37.05 1.1613 3240 55 200 12
270 1.5 Comp. Ex. 11 20 Asymmetric Alumina 37.05 1.1613 3240 55 200
12 270 1.5 Comp. Ex. 12 21 Asymmetric Alumina 40.15 0.5561 3240 55
400 12 270 1.5 Comp. Ex. 13 22 Asymmetric Alumina 40.15 0.5561 3240
55 400 12 270 1.5 Comp. Ex. 14 23 Asymmetric Alumina 40.15 0.5561
3240 55 400 12 270 1.5 Comp. Ex. 15 24 Symmetric Alumina 87.53
0.0084 3240 31 1500 12 270 1.5 Comp. Ex. 16 27 Symmetric Alumina
151.32 -0.1702 3240 31 1500 12 270 1.5 Comp. Ex. 17 28 Symmetric
Alumina 151.32 -0.1702 3240 31 1500 12 270 1.5 Comp. Ex. 18 33
Asymmetric Aluminosilicate 60.41 2 1.2 99 1440 55 0.55 16 90 2
Comp. Ex. 19 34 Asymmetric Aluminosilicate 60.41 2 1.2 99 1440 55
0.55 16 90 2 Comp. Ex. 20 35 Asymmetric Aluminosilicate 60.41 2 1.2
99 1440 55 0.55 16 90 2 Comp. Ex. 21 42 Symmetric Alumina 50.01
0.3117 180 30 600 6 30 1 Comp. Ex. 22 43 Symmetric Alumina 50.01
0.3117 180 30 600 6 30 1 Comp. Ex. 23 44 Symmetric Alumina 50.01
0.3117 180 30 600 6 30 1 Comp. Ex. 24 48 Symmetric Alumina 50.01
0.3117 1380 30 600 6 230 1 Comp. Ex. 25 49 Symmetric Alumina 50.01
0.3117 1380 30 600 6 230 1 Comp. Ex. 26 53 Symmetric Metal 64
0.0003 1385.44236 47.7 500000 42 Flat 1.3 plate Comp. Ex. 27 5
Symmetric Resin 72 0.0225 900 40 4000 15 60 3 indicates data
missing or illegible when filed
TABLE-US-00006 TABLE 6 Flow speed test data Time until Solvent
Applied entire solvent Results Solvent amount pressure passes
through Flow rate Q Pore area A Flow speed V Nanosight (NS-300)
Condition No. type [mL] [MPaG] [sec.] [m.sup.2/s] [m.sup.2] [m/s]
A.sup.Note B.sup.Note C.sup.Note Comp. Ex. 1 4 Pure water 200 0.1
393.09 0.0000051 1.3 080E-03 0.000374 111.7 1.5 E+07 0.8 Comp. Ex.
2 5 Pure water 200 0.5 148. 0.000001 1.3 080E-03 0.000988 90.0
2.26E+07 1.1 Comp. Ex. 3 12 Pure water 200 0.1 700 0.00000029 1.3
080E-03 0.000210 100.3 1.0 E+07 0.5 Comp. Ex. 4 13 Pure water 200
0.5 300 0.00000067 1.3 080E-03 0.000490 99.5 2. 8E+07 1.3 Comp. Ex.
5 14 Pure water 200 0.9 120 0.00000167 1.3 0E-03 0.001225 107.6
4.80E+07 2.4 Comp. Ex. 6 15 Pure water 200 0.1 6254 0.00000003 1.
080E-03 0.000024 102.3 3.9 E+0 0.2 Comp. Ex. 7 16 Pure water 200
0.5 1754 0.00000011 1.3 080E-03 0.000084 98.5 8.78E+06 0.4 Comp.
Ex. 8 17 Pure water 200 0.9 803.54 0.00000025 1.3 080E-03 0.000183
99.8 9.99E+08 0. Comp. Ex. 9 18 Pure water 200 0.1 3 0.00000054
1.78200E-03 0.000304 82.4 2.42E+07 1.2 Comp. Ex. 10 19 Pure water
200 0.5 12 .8 0.00000168 1.78200E-03 0.000885 108.0 2.80E+07 2.3
Comp. Ex. 11 20 Pure water 200 0.9 28.87 0.00000 3 1.78200E-03
0.003888 69.1 6.30E+07 3.2 Comp. Ex. 12 21 Pure water 200 0.1 21 .5
0.000000 1 1.78200E-03 0.000511 102.6 3.88E+07 1.9 Comp. Ex. 13 22
Pure water 200 0.5 38.91 0.00000514 1.78200E-03 0.002884 75.1
4.88E+07 2.4 Comp. Ex. 14 23 Pure water 200 0.9 13.3 0.00001499
1.78200E-03 0.008413 7 . 5.76E+07 2.9 Comp. Ex. 15 24 Pure water
200 0.1 112. 0.00000177 1.00440E-03 0.001766 127.7 5.4 E+07 2.7
Comp. Ex. 16 27 Pure water 200 0.1 21.96 0.00000032 1.00440E-03
0.000320 91.5 4.2 E+07 2.1 Comp. Ex. 17 28 Pure water 200 0. 40.19
0.00000 98 1.00440E-03 0.004955 121.7 5. E+07 2. Comp. Ex. 18 33
Pure water 200 0.1 29265 0.00000001 7.92000E-04 0.000009 89.8
2.38E+08 0.1 Comp. Ex. 19 34 Pure water 200 0. 110 1 0.00000002
7.92000E-04 0.000023 98.8 6.18E+0 0.3 Comp. Ex. 20 35 Pure water
200 0.9 5845 0.00000003 7.92000E-04 0.000043 102.3 8.53E+0 0.4
Comp. Ex. 21 42 Pure water 200 0.1 2001.35 0.00000010 5.40000E-05
0.001851 102.6 2.38E+07 1.2 Comp. Ex. 22 43 Pure water 200 0. . 5
0.00000020 5.40000E-05 0.003720 104.4 5.82E+07 2.9 Comp. Ex. 23 44
Pure water 200 0.9 780.41 0.0000002 5.40000E-05 0.004746 101.4
5.10E+07 2.6 Comp. Ex. 24 46 Pure water 200 0.1 788 0.0000002
4.14000E-04 0.000813 95.7 4.96E+07 2.5 Comp. Ex. 25 49 Pure water
200 0.5 301.47 0.000000 4.14000E-04 0.001602 149.2 4.75E+07 2.4
Comp. Ex. 26 53 Pure water 200 0.1 52 0.00000385 6.60440E-04
0.005824 112.7 3.72E+07 1.9 Comp. Ex. 27 5 Pure water 200 0.00 44
0.00000031 3.60000E-04 0.000863 99.9 2.20E+07 1.1 .sup.Note A:
Bubble diameter [nm] B: Bubble concentration [bubbles/mL] C: Bubble
concentration [particles/frame] indicates data missing or illegible
when filed
TABLE-US-00007 TABLE 7 Pore Condition No. Flow speed V
concentration Judgement Comp. Ex. 23 44 0.004746 5.10E+07
Unacceptable Comp. Ex. 17 28 0.004955 5.68E+07 Unacceptable Comp.
Ex. 14 23 0.008413 5.76E+07 Unacceptable Ex. 28 54 0.009769
7.30E+07 Acceptable Ex. 12 29 0.011180 6.82E+07 Acceptable Ex. 10
25 0.013503 8.18E+07 Acceptable
(1) Element Structure
[0137] For the element structure, the term "symmetric structure"
means that the element has a single structure. The term "asymmetric
structure" means that inner and outer portions of the element have
different structures. More specifically, the asymmetric structure
is a two-layer structure in which the outer portion (i.e., outer
layer) of the element is smaller in average pore diameter than the
inner portion (i.e., inner layer) of the element.
(2) Element Material
[0138] The element material is the material forming the element.
Therefore, the element is a porous member formed of this
material.
(3) Contact Angle
[0139] As is well known, the contact angle is the angle between the
free surface of a stationary liquid and a wall at a point where the
free surface of the liquid contacts the wall.
[0140] In Experimental Example 1, a DropMaster series (DMo-501) was
used to measure the contact angle by a droplet method. The liquid
used was pure water (4 .mu.L), and the contact angle 100 ms after
the liquid was dropped was obtained.
[0141] The maximum pore diameter DBP [m] of the pores, the surface
tension .gamma. [N/m] of the liquid, the contact angel 0 [rad], and
the bubble point pressure P [Pa] satisfy the relation represented
by formula (1) below. The maximum pore diameter DBP [m] of a pore
is the diameter of the pore when the pore is assumed to be a
circular pore.
DBP=4.gamma. cos .theta./P (1)
(4) Bubble Point Pressure
[0142] For example, a plate-shaped element is immersed in a liquid
such as isopropyl alcohol and is held horizontally. Then air is
supplied from the lower side of the element, and the pressure of
the air is increased. When the pressure reaches a certain value, an
air bubble is first generated from a pore with a maximum pore
diameter. The pressure at this point is referred to as the bubble
point pressure. The maximum pore diameter can be determined from
the bubble point pressure using formula (1) above.
(5) Pure Water
[0143] In Experimental Example 1, the liquid used was pure water.
The pure water is generally a liquid subjected to
demineralization/deionization treatment using, for example, an
ion-exchange resin and has an electric conductivity in a prescribed
range and a TOC (total organic carbon) in a prescribed range.
[0144] In Experimental Example 1, as shown in FIG. 8 below, the
conductivity (i.e., the electric conductivity) [.mu.S/m]. TOC
(total organic carbon) [.mu.g/L], ICP-MS (ion concentration), pH,
DO (dissolved oxygen) [mg/L], and ATP (viable count) [RLU] were
examined for 5 different types of pure water (5 samples: N1 to N5)
used in the experiment.
[0145] The pH and the electric conductivity were measured using a
pH/water quality meter D-74 manufactured by HORIBA.
[0146] The TOC was measured using TOC-VWP manufactured by Shimadzu
Corporation. The ICP-MS was measured using SCIENTIFIC iCAP Q
manufactured by Thermo Fisher. The DO was measured using OM-71
manufactured by HORIBA Ltd. The ATP was measured using Lumitester
PD-30.
[0147] A NanoSight NS-300 (hereinafter referred to simply as
NanoSight) was used to examine the bubble diameter [nm], the bubble
concentration [bubbles/mL], and the bubble concentration
[particles/frame]. The term [particles/frame] represent the number
of particles in one image obtained through the measurement using
the NanoSight, and 1500 frames are captured in one measurement.
Specifically, the average of the numbers of particles in 1500
frames is represented by [particles/frame].
[0148] The results are shown in Table 8 below.
[0149] The pure water used in the experiment has an electric
conductivity within the range of 47.9 to 83.2 [.mu.S/m] and a TOC
value within the range of 5 to 40.1 [.mu.g/L]. Water whose electric
conductivity and TOC value fall within these ranges can be regarded
as pure water.
TABLE-US-00008 TABLE 8 N1 N2 N3 N4 N5 Ave Max. Min. S.D. Electric
conductivity [uS/m] 58.6 47.9 83.2 59.6 66.7 63.2 3.2 47.9 13.043
TOC[.mu.g/L] 28.4 5 40.1 22.5 37.5 26.7 40.1 5 14.032 ICP-MS 7 4 8
6 7 6.4 8 4 1.517 pH 5.83 6.02 5.99 6.21 6.08 6.026 6.21 5.83 0.138
DO[mg/L] 7.34 8.01 8.21 7. 5 7. 4 7.83 8.21 7.34 0.342 ATP[RLU] 1.3
0.7 2. 1.2 2.2 1.6 2. 0.7 0.778 NanoSight Bubble diameter 98.6 96.4
100.2 102.9 103.2 100.2 103.2 96.4 2.884 (NS-300) [nm] Bubble
concentration 3.81E+05 1.61E+05 2.98E+06 7.81E+05 1.78E+06 1.22E+06
2.98E+06 1.61E+05 1.17E+06 [bubbles/mL] Bubble concentration 0.0
0.0 0.2 0.0 0.1 0.0618 0.15 0.009 0.058 [particles/frame] indicates
data missing or illegible when filed
(6) Effective Area of Element
[0150] In Experimental Example 1, a cylindrical element shown in
FIG. 6 was used. Therefore, the area of the side surface (i.e., the
outer circumferential surface of the cylinder) of the element
through which the liquid can pass is used as the effective area of
the element.
[0151] The element length is the length of the element in its axial
direction, and the element outer diameter is the diameter of the
outer circumference of the element as it is viewed in the axial
direction. Therefore, the effective area of the element can be
determined from the element length and the element outer diameter.
The film thickness is the thickness (radial dimension) of the
cylindrical element.
(7) Surface Porosity
[0152] The surface porosity is the surface ratio of the pores to
the effective area of the element. The surface porosity can be
determined by obtaining an image of the surface of the element
using, for example, a scanning electron microscope (SEM),
binarizing the image (into a black-and-white image), and
determining the ratio of the area of the black portions
(specifically, the ratio of the black portions indicating pores to
the effective area of the element).
(8) Pore Diameter (i.e., Average Pore Diameter)
[0153] The pore diameter is the diameter of a pore when the pore is
assumed to be a circular pore (specifically, the average of the
diameters of a large number of pores: the average pore diameter).
In this case, the pore diameter was measured using mercury
porosimetry. In the mercury porosimetry, AutoPore IV 9510
(manufactured by Shimadzu Corporation) was used.
(9) Solvent Type
[0154] The solvent type means a liquid in which fine bubbles are
generated and is pure water in the experiment.
(10) Solvent Amount
[0155] The solvent amount means the amount (VO [mL]) of the liquid
supplied to the first tank.
(11) Applied Pressure
[0156] The applied pressure is the pressure of the gas supplied
from the gas cylinder to the first tank (i.e., the pressure inside
the first tank).
(12) Time Until Entire Solvent Passes Through
[0157] The time until the entire solvent passes through is the time
[sec.] until the entire liquid in the first tank (i.e., the liquid
in the inner space of the element) moves to the second tank (i.e.,
the outer space of the element).
(13) Flow Rate Q
[0158] The flow rate Q [m.sup.3/s] is the amount [m.sup.3] of the
liquid moved from the inner side of the element to the outer side
per unit time [sec]. The flow rate Q can be determined by dividing
the "solvent amount" by the "time until entire solvent passes
through."
(14) Pore Area A
[0159] The pore area A [m.sup.2] is the total pore area on the
outer surface of the element. Specifically, the pore area A is the
total area of the pores in the effective area of the element. The
total pore area can be determined by obtaining an image of the
surface of the element using, for example, an SEM, binarizing the
image (into a black-and-white image), and determining the total
area of the black portions representing the pores.
(15) Flow Speed V
[0160] The flow speed V [m/s] is the flow speed of the liquid
during passage through the pores of the element and can be
determined by dividing the flow rate Q [m.sup.3/s] by the pore area
A [m.sup.2].
(16) Bubble Diameter and Bubble Concentration
[0161] The bubble diameter and the bubble concentration were
measured by the NanoSight.
<Evaluation>
[0162] In each of the samples of the Examples, the flow rate is
0.009769 [m/s] or more, and these samples realize high bubble
concentrations and are preferable. For example, even sample No. 54
whose liquid flow speed is smallest realizes a bubble concentration
of 7.30.times.10.sup.7 [bubbles/mL] and is preferable.
[0163] As is clear from Tables 1 to 4, in each of the samples of
the Examples, the pore diameter (i.e., the average pore diameter)
of the element is 1.5 .mu.m to 500 .mu.m. This shows that when the
pore diameter falls within this range, a high bubble concentration
can be obtained.
[0164] The lower limit (1.5 .mu.m) of the average pore diameter is
shown as the average pore diameters of samples Nos. 1 to 3 etc.,
and the upper limit (500 .mu.m) of the average pore diameter is
shown as the average pore diameters of samples Nos. 50, 51, 52,
etc.
[0165] As is clear from Tables 1 to 4, in each of the samples of
the Examples, the surface porosity of the element is 24% to 47.7%.
This shows that when the surface porosity falls within this range,
a high bubble concentration can be obtained as described above.
[0166] The lower limit (24%) of the surface porosity is shown as
the surface porosities of samples Nos. 6 to 11, and the upper limit
(47.7%) of the surface porosity is shown as the surface porosities
of samples Nos. 54 and 55.
[0167] Moreover, as is clear from Tables 1 to 4, in each of the
samples of the Examples, the contact angle of the liquid (pure
water) on the surface of the element is 38.8.degree. to
151.32.degree.. When the contact angle is within this range, a high
bubble concentration can be obtained as described above.
[0168] The lower limit (38.8.degree.) of the contact angle is
determined based on the contact angle in sample No. 30 etc., and
the upper limit (151.32.degree.) of the contact angle is determined
based on the contact angle in sample No. 29.
5-2. Experimental Example 2
[0169] As described above, the conventional techniques in Japanese
Patent Application Laid-Open (kokai) No. 2002-301345 and Japanese
Patent Application Laid-Open (kokai) No. 2017-217585 differ totally
from the present disclosure. Specifically, in these techniques,
large air bubbles contained in water in the pre-stage tank are
sheared to form fine air bubbles. These techniques require shearing
of the bubbles.
[0170] In contrast, in the present disclosure, as shown in, for
example, the first embodiment, the bubble diameter of the bubbles
contained in the first tank is almost the same as the bubble
diameter of the bubbles contained in the second tank. Namely, in
the technique of the present disclosure, when, for example, the
liquid in the first tank passes through the pores in the porous
element, a rapid change in pressure occurs, and fine bubbles are
thereby generated. The bubble diameter hardly changes due to
passage through the element (i.e., the bubble diameter after
passage through the element is almost the same as the bubble
diameter before passage through the element). To cause the above
phenomenon to occur, the flow speed must be 0.009769 [m/s] or more
as described above.
[0171] In Experimental Example 2, in view of the above findings, a
change in bubble diameter due to passage of the liquid (pure water)
through the element (i.e., the difference between the bubble
diameter before passage of the liquid through the element and the
bubble diameter after passage of the liquid through the element)
was examined.
[0172] In Experimental Example 1 described above, the NanoSight was
used to examine the bubble diameters of the fine bubbles in the
liquid in the first tank. Usually, fine bubbles are present in a
liquid, although their amount is small.
[0173] In the samples of the Examples, the average bubble diameter
of the fine bubbles in the liquid before passage through the
element was 100.26 nm.
[0174] In the samples of the Examples, the average bubble diameter
of the fine bubbles in the liquid after passage through the element
was 100.80 nm (see the average value (Ave.) for the Examples in
Table 4).
[0175] As can be seen from the above, the liquid that has passed
through the element has an increased fine bubble concentration, but
the average bubble diameter hardly changes due to passage of the
element (i.e., the bubble diameter after passage through the
element is almost the same as the bubble diameter before passage
through the element).
5-3. Experimental Example 3
[0176] In Experimental Example 3, commercial nozzle-type fine
bubble generation devices available from two companies were used to
examine the state of fine bubbles generated.
[0177] In the nozzle type, a pump is used to cause a liquid (pure
water) to flow through a tube having a wall surface including pores
formed therein, and air is supplied to an intermediate portion of
the tube from the outside through the pores.
[0178] In Experimental Example 3, the bubble concentration of fine
bubbles generated was measured using the NanoSight under the
conditions shown in Table 9 below. Specifically, the bubble
concentration in the case of one pass (the liquid was not
circulated) and the bubble concentration in the case where the
liquid was circulated using a pump for 60 minutes were
measured.
TABLE-US-00009 TABLE 9 Solvent Pump flow Generation Pump amount
rate Gas time Company A MD- 1 L 33 L/min Air (natural 60 min. 70RZ
intake) Company B MD- 1 L 33 L/min Air (natural 60 min. 70RZ
intake)
[0179] With these fine bubble generation devices from the two
companies, only bubble concentrations lower than the reliable range
of the NanoSight (i.e., 2.times.10.sup.8 [bubbles/mL] or more)
could be measured. The experimental data is shown in Table 10
below.
TABLE-US-00010 TABLE 10 After circulation for 60 One pass
[bubbles/mL] minutes [bubbles/mL] Company A 1.05E+04 5.12E+06
Company B 7.05E+04 1.08E+07
[0180] Notably, in a concentration range lower than the reliable
range of the NanoSight, errors are large, and the reliability is
not sufficient.
5-4. Experimental Example 4
[0181] In Experimental Example 4, as shown in FIGS. 7 and 8, the
liquid used was pure water, and fine bubbles were generated using
the fine bubble generation devices of Examples used in Experimental
Example 1 and various fine bubble generation devices other than
those of the present disclosure. Various characteristics of the
fine bubble liquids (specifically, different types of fine bubble
water) were examined. When the characteristics were examined,
glass-made containers of the same type were used as containers, in
which the fine bubble liquids were placed, so that measurement
environments were as close to each other as possible.
[0182] The details will next be described.
<Samples, Devices, Etc.>
[0183] In FIGS. 7 and 8, "T26: ceramic" represents sample No. 26,
which is an Example, and "T55: metal" represents sample No. 55
which is an Example. "T59: resin" represents sample No. 59 which is
an Example.
[0184] The fine pore-type device is a fine pore-type fine bubble
generation device using the ceramic-made element from the company C
(i.e., a Comparative Example). In this fine bubble generation
device, a porous element (i.e., a pipe) having a closed forward end
is submerged in a liquid, and a gas is supplied to the pipe to
generate fine bubbles on the outer side of the pipe.
[0185] The characteristics in the first test are the
characteristics of the fine bubble liquid after fine bubbles are
first generated under the following conditions, and the
characteristics in the fifth test are the characteristics of the
fine bubble liquid after fine bubbles are generated five times
under the same conditions.
(Experimental Conditions)
[0186] Setting pressure: 0.11 MPa
[0187] Treatment time: 1 hour
[0188] Solvent: pure water 500 mL
[0189] Gas type: nitrogen gas
[0190] Gas flow rate: 600 mL/min
[0191] A well-known circulation-type pressurized dissolution device
and a well-known circulation-type gas-liquid shearing device were
used as other Comparative Examples so as to generate fine bubbles,
and the characteristics of the fine bubble liquids were
examined.
<Evaluation>
[0192] FIG. 7A shows the results of the examination of the pH value
of each fine bubble liquid. As can be seen from FIG. 7A, the pH
value of each of the fine bubble liquids produced by the samples of
the Examples is close to the pH value of pure water. However, the
fine bubble liquid produced in the first test with the fine
pore-type has a large pH value of 7 or more.
[0193] FIG. 7B shows the results of the examination of the electric
conductivity of each fine bubble liquid. As can be seen from FIG.
7B, the electric conductivity of each of the fine bubble liquids
produced by the samples of the Examples is close to the electric
conductivity of pure water. However, the fine bubble liquid
produced in the first test with the fine pore-type has a very high
electric conductivity of 738 [.mu.S/m]. In the case of use of other
generation types also, an increase in electric conductivity is
found.
[0194] FIG. 7C shows the results of the examination of the ATP
value of each fine bubble liquid. As can be seen from FIG. 7C, the
ATP value of each of the fine bubble liquids produced by the
samples of the Examples is close to the ATP value of pure water.
However, the fine bubble liquid produced in the first test with the
fine pore-type has a very high ATP value of 55.
[0195] FIG. 8A shows the results of the examination of the TOC
value of each fine bubble liquid. As can be seen from FIG. 8A, the
TOC value of each of the fine bubble liquids produced by the
samples (T26 and T55) of Examples is close to the TOC value of pure
water. The fine bubble liquids produced by the sample (T59) which
is an Example, the circulation-type pressurized dissolution device,
and the circulation-type gas-liquid shearing device, respectively,
have large TOC values. In the case of use of the fine pore-type,
the TOC value could not be measured.
[0196] FIG. 8B shows the results of the examination of the ICP-MS
value of each fine bubble liquid. As can be seen from FIG. 8B, the
ICP-MS value of each of the fine bubble liquids produced by the
samples of the Examples is close to the ICP-MS value of pure water.
However, the fine bubble liquid produced in the first test with the
fine pore-type has a very high ICP-MS value of 548 [ppb].
5-5. Experimental Example 5
[0197] In Experimental Example 5, whether fine bubbles generated in
a fine bubble generation device were actually fine bubbles or
particles such as fine dust particles (i.e., solid particles) was
examined. Specifically, since the NanoSight occasionally counts
fine particles as fine bubbles, how close the actually measured
particle concentration (i.e., the bubble concentration in the case
of bubbles) was to the concentration of the fine bubbles was
examined.
<Samples, Devices, Etc.>
[0198] Liquids used for the particle concentration measurement are
almost the same as those in Experimental Example 4. Specifically,
pure water, the fine bubble liquid obtained by T26, the fine bubble
liquid obtained by the fine pore-type device (in the first test),
the fine bubble liquids obtained by the circulation-type
pressurized dissolution device and the circulation-type gas-liquid
shearing device, and the fine bubble liquids obtained by T55 and
T59 were used. In addition, a liquid obtaining by dispersing Latex
particles in a solvent (pure water) was also used.
<Details of Experiment>
[0199] In Experimental Example 5, each of the liquids of the
samples was first frozen and then melted, and the particle
concentrations before and after freezing were examined using the
NanoSight.
[0200] When a liquid containing air bubbles and solid particles is
cooled and frozen, many bubbles disappear. Therefore, this freezing
method enables determination of the amount of air bubbles actually
present in the liquid before freezing through measurement of the
particle concentration of the liquid before and after freezing.
[0201] Specifically, a method for distinguishing air bubbles and
solid particles from each other using a slow freezing-thawing
method disclosed in the 8th International Symposium on Fine Bubbles
was used. More specifically, each of the samples was cooled and
frozen at a prescribed cooling rate (e.g., 0.57.times.10.sup.-2
[K/s]) and then heated and melted at a prescribed heating rate
(e.g., 0.76.times.10.sup.-2 [K/s]), and the particle concentration
of the liquid was measured before and after freezing.
<Evaluation>
[0202] FIG. A shows the particle concentrations before and after
freezing of samples obtained in Experimental Example 5. In this
graph, the particle concentrations of each sample are shown in a
two-bar chart. The left bar represents the particle concentration
before freezing, and the right bar represents the particle
concentration after freezing. FIG. DB is a graph obtained by
modifying the graph of FIG. A in such a manner that the particle
concentration of each sample after freezing is determined with the
particle concentration before freezing (i.e., before defoaming) set
to 100. In FIGS. A and DB, the left bar in each pair of bars
represents the particle concentration before defoaming, and the
right bar represents the particle concentration after
defoaming.
[0203] As is clear from FIGS. A and DB, in the case of the sample
T26 which is an Example, the particle concentration after freezing
is lowered largely. Specifically, as shown in Table 11 below, the
defoaming ratio of the sample T26 which is an Example is 88.36%,
and almost all the particles are air bubbles. The defoaming ratio
is an index indicating the ratio of air bubbles to the detected
particles and is defined as "(the particle concentration of the
liquid after freezing)/(the particle concentration of the liquid
before freezing).times.100."
TABLE-US-00011 TABLE 11 Deforming ratio [%] Fine Fine
circulation-type Circulation-type pore-type pore-type pressurized
gas-liquid T26 device: device: dissolution shearing T55 T59 Latex
ceramic first test fifth test device device metal resin resin 88.36
15.20 72.74 65.98 78.95 82.35 87.37 11.15
[0204] As is clear from Table 11 etc., in the case of the sample
T55 which is an Example, the defoaming ratio was 82.35%, which
shows that almost all the particles were air bubbles. In the case
of the sample T59 which is an Example, the defoaming ratio was
87.37%, which shows almost all the particles were air bubbles.
[0205] However, in the first test with the fine pore-type device
which is one Comparative Example, the defoaming ratio was 15.20%,
which shows that almost all the particles were solid particles. In
the fifth test with the fine pore-type device, although the
defoaming ratio was 72.74%, the particle concentration before
defoaming was 2.59 E+07 [bubbles/mL] and was small (see FIG.
A).
[0206] In the case of the circulation-type pressurized dissolution
device which is another Comparative Example, the defoaming ratio
was 65.98%, and the amount of solid particles was larger than that
in the Examples.
[0207] Similarly, in the case of the circulation-type gas-liquid
shearing device which is still another Comparative Example, the
defoaming ratio was 78.95%, and the amount of solid particles was
larger than that in the Examples.
[0208] In the sample containing the Latex particles added thereto,
the defoaming ratio was 11.15%.
6. OTHER EMBODIMENTS
[0209] The present disclosure is not limited to the embodiments
described above, etc., and it will be appreciated that the present
disclosure can be implemented in various forms so long as they fall
within the technical scope of the disclosure.
[0210] (1) For example, the element may have any of various shapes
such as the shape of a tube with a closed end, the shape of a tube
which is open at opposite ends in the axial direction, and the
shape of a plate.
[0211] (2) The material used for the element may be any of various
materials other than ceramics such as metals and resins.
[0212] (3) When an on-off valve is provided in a flow channel for
supplying liquid or gas or a flow channel for withdrawing liquid,
the operation of the on-off valve may be controlled by, for
example, a computer.
[0213] For example, the amount of the liquid supplied to the first
tank and the flow rate of the liquid may by measured by sensors,
and the pressure inside the first tank may be measured by a sensor.
Then the on-off operation of the on-off valve may be controlled
according to the values measured by the sensors such that the flow
rate, etc. of the liquid and the pressure inside the first tank
become equal to respective target values. Therefore, the structures
for generating fine bubbles can be arranged in-line.
[0214] (4) The function of one component in any of the above
embodiments may be distributed to a plurality of components, or the
functions of a plurality of components may be realized by one
component. Part of the structure of each of the above embodiments
may be omitted. At least part of the structure of each of the above
embodiments may be added to or partially replace the structures of
other embodiments. All modes included in the technical idea
specified by the wording of the claims are embodiments of the
present disclosure.
* * * * *